Bags are a common form of packaging and are readily available. Bags are generally flexible; they easily conform to the shape of the item being retained; and they are relatively inexpensive to produce. Over the years, methods for making flat bottom bags have changed, from manually folding paper sheets to form the bags, to mechanical processes for automatically folding paper sheets to form the bags.
A common bag configuration is a flat bottom bag with gusseted sides. Both the standard, brown paper grocery bag and brown paper lunch bag are such flat bottom bags. A standard flat bottom bag is illustrated in FIG. 13, showing the various flaps and folds. Such a configuration, in addition to the paper material, is not resistant to water or other liquid, due to the bottom fold configuration. Indeed, such a construction easily allows passage of liquid therethrough.
Other bottom fold configurations for flat bottom bags are known.
One method for folding paper flat bottom bags (also referred to as block-shaped bottom bags) having a fold configuration different than the grocery bag, discussed above, is described in U.S. Pat. No. 3,266,387, Finke et al. The bag produced by Finke et al. is illustrated in FIG. 14, showing the various flaps and folds, The process of Finke et al. begins tubular bags (i.e., unfinished bags having a non-sealed bottom). The teachings of Finke et al. include folding the bottom, changing the bag orientation direction, and then raising the corner pleats.
Improvements are desirable.